One of the most common circuits in the market is the water level indicator. But most of these circuits fault corrosion of metal electrodes due to electrolytic reaction. This fault can be minimized effectively by using alternating current instead of direct current supply. Here we design and verify a circuit called electrolysis proof water level indicator using a COMOS IC which has profitably exploited the normally unused property of CMOS devices.
Other Water level indicators and controller circuits posted on bestengineeringprojects.com
- Ultrasonic Water Level Meter
- Water Level Indicator Circuit using 7-Segment
- Water Level Controller Using NE555
Description of Electrolysis Proof Water Water Level Indicator Circuit:
The water level indicator circuit is built around a hex inverter buffer CMOS IC. The water level indicator circuit has six level indications because it contains six independent inverter units. When the water levels with the sensor element in output go high making the respective LED ‘ON’. On the further rise in the water level, more LEDs will get switched ‘ON’ in ascending order.
The value of resistance R in the water level indicator circuit is found to be around 12MΩ in the case of tubes of 1.2-meter depth and equally spaced discs as shown in the circuit diagram of the water level indicator. Its value may be changed considerably, depending on the minerals and other chemical contents of water, the spacing between the sensors, the position of the sensors, and their surface area. The value of R can be selected to give the water level indicator circuit any desired sensitivity up to a maximum of about 20 MΩ.
Sensor elements can be inserted in a screw-capped glass tube of 2cm diameter and length equal to the depth of the water tank which is open at the base end. The sensitivity of the water level indicator circuit is relatively independent of the lead length. All seven leads have to be insulated properly to avoid possible short-circuit.
PARTS LIST OF WATER LEVEL INDICATOR CIRCUIT
| Resistor (all ¼-watt, ± 5% Carbon) |
| R1 = 200 KΩ, ½ Watt
R2 = 100 Ω, 1Watt R3 – R8 = 220 Ω, ½ or ¼ Watt R9 – R14 = See text |
| Capacitors |
| C1 – C6 = 1 µF/25V electrolytic capacitors |
| Semiconductors |
| IC1 = CD4049 (CMOS Hex Inverting Buffer/Converter)
ZD1 – ZD2 = 1Z5.1 or equivalent (5.1V, 1W) zener diode D1 – D6 = DR25 or DR50 diodes D7 = 1N4001 or equivalent diode LED1 = LED6 = RED LEDs |
| Miscellaneous |
| X1 = 230V to 9V mains transformer, with 200mA secondary
SW1 = 250V AC SPDT Switch NEON Lamp Sensor Elements |